1. Field of the Invention
The present invention relates to a method and apparatus for processing coded information received through a telephone line during the inter-ringing periods. More particularly, the present invention relates to a method and apparatus allowing a called phone subscriber to know who the calling party is when his phone set receives a call followed by the reception of a pre-established code and before the called party answers the phone. The validation of the code received by the apparatus of the present invention may also be used to carry out several subsequent operations.
2. Description of the Prior Art
A phone subscriber is commonly pestered by innumerable unwanted phone calls, even in the small hours or when he is busy and he does not desire to be perturbed. Until now, no effective method is known to obviate such inconveniences. The most simple method used is to have a private exchange attended by an operator. However it may happen that the operator is not sure of the importance of the call; in such case the operator must assume the responsibility of transferring the communication, in which case said operator must interrupt the called party or, in the opposite case, look for an excuse for obviating said interruption. In this later case it may happen that the operator was wrong in evaluating the importance of the true urgency of the call. A device supposedly intended for obviating inconveniences of this sort is the automatic answering recorder. However, this kind of apparatus does not allow to know if the calling party is a desired one, before the latter hangs up. Such an apparatus is more useful for knowing which persons have called during a period of absence of the phone subscriber. Later on he may replay all the recorded messages which have been left by the calling parties during his absence. It is not practical to put in operation such an apparatus when the phone subscriber is present, because he can loose important or simply desired calls. It is also possible to resort to a company rendering answering services. While such services offer obviously several advantages, there are also various drawbacks. One of them is that the answering service retains the phone line of the phone subscriber during all the time the service is rendered. Another drawback is that the operators of such services become acquainted with the nature of the received messages and thus there is no privacy or secrecy. Still another drawback is that there is a considerable delay between the reception of the message by the answering service and the moment at which the called subscriber becomes acquainted therewith. Another device used by some phone subscribers to get privacy, and which is available on the market, is a simple switch which is connected in series with the circuit of the ringing bell of the phone set. When the switch is open, the bell will not sound and thus the phone subscriber will never become aware of the fact that the phone call is being made to him. This is obviously a very inconvenient method since the phone subscriber may miss one or more very important and/or urgent calls. The phone subscriber has no means to know if a call is being made and if the calling party may be or not a desired one. Another very important drawback is that if the phone subscriber forgets to close the switch when he desires to be again in conditions of receiving calls, he may remain incommunicated during several hours, or even days, without being aware of the fact.